21 Mind-Blowing Now-Extinct Lifeforms - mental_floss on YouTube (Ep.51)

Hi, welcome to Mental Floss on YouTube

I'm Emily Grassley of the Brain Scoop sitting in the Chicago Field Museum, and today we're going to talk about some mind-blowing and unfortunately

and sometimes not so unfortunately, extinct lifeforms. It wouldn't be right to start off talking about anything but the earliest evidence of life itself

which are layered structures called stromatolites. Stromatolites occurred when early bacteria and microbial life formed mats that turned into sedimentation on the bottom of the ocean some 3.5 billion years ago

So life began. But not a lot else happened for the next 3 billion years, so let's fast forward to trilobites

Trilobites! These early arthropods, aka invertebrates with hard bodies like our modern-day lobsters and spiders

are some of the most diverse forms of early life on the planet. Trilobites were around for hundreds of millions of years, from about 521 million years ago to up to 250 million years ago before they all died out in the Permian mass extinction

But we know of more than 20,000 different species of trilobites today

To start off a list of things I am pretty glad no longer exist are the Eurupterids, which were giant sea scorpions, and we're talking about invertebrates that were around 8 feet or 2 and a half meters in length

That's the size of a crocodile. These predatory cannibals show up in the fossil record around 460 million years ago

and thankfully died off around 248 million years ago. It wouldn't be right to glorify history, so let's talk about how some early life forms subsisted

like this poop-eating snail. This early gastropod from the Silurian period existed about 443 to 419 million years ago

And when there's not a lot of food around, you go to what's reliable, in this case, feces

This early mollusk has been fossilized attached to the end of a crinoid, a simple kind of animal that looks and acts like a plant

And here it shall forever be frozen in time as evidence of its dirty poop-eating habits

The Dunkle Osseus was one of the largest plate-skinned armored fishes ever to live, and it swam around 380 to 360 million years ago

Scientists here at the Field Museum have concluded that it had a bite force comparable to that of T and our modern crocodiles It would have used up to 1100 pounds of force and closed its mouth so quickly that it

would have created suction in order to draw in its prey and oh my god I am so

glad they don't exist anymore. Another ancient ancestor we owe a lot to is the

Tiktaalik also known as a fishapod. This ingenious creature serves as a

It's a turning point in the evolution of life, because at about 375 million years ago, it

learned how to walk onto land. This ultimate grandfather of tetrapods was half fish and half amphibian, and there is

evidence that it had gills as well as lungs. If we're going to be talking about early life forms, I have to make a mention of the Tully Monster

This unique soft-bodied invertebrate lived about 300 million years ago, and so far is

unique to the Illinois region. So naturally, they went ahead and made it the state fossil

The Tully monster is unique because of its weird cuttlefish-like tail, its proboscis with teeth, and its adorable protruding little eyeballs

Adaphosaurus, which you may recognize, was an early synapsid, which is kind of like an early mammal-like reptile

They existed from around 303 to 275 million years ago, and are most notable for their gigantic vertebral spine

Unique to Adaphosaurus are the crossbars on these spines. Nobody can quite make up their minds what they were used for and debates arise on whether or not they were used for food storage or thermoregulatory reasons

Another animal I'm increasingly glad no longer exists is the Helicoprion, an ancient shark from the early Triassic that lived around 250 million years ago

Not much is known about this terrifying creature other than instead of normal teeth, it essentially had a circular saw growing out of its mandible

Scientists refer to this as a tooth whirl and provided a never-ending regeneration of permanent teeth

We couldn't very easily have a list about mind-blowing now-extinct lifeforms without at least giving a nod to the Tyrannosaurus Rex

Specifically, this lady behind me, who is the largest and most complete example of her species ever to be discovered

making her one of the largest land predators to ever walk the planet

You can't tell me that isn't mind-blowing. On the subject of unbelievably gigantic predators we can help but talk about the pterosaurs especially this one Quetocoatlas which stood as tall as a giraffe and had a wingspan up to 40 feet As previously mentioned in the 50 Common Science Misconceptions video

pterosaurs were lizards, not dinosaurs or birds, thus becoming the closest living thing to a dragon as ever existed

Fast forwarding in time, we've got weirdos like Enterotherium, a moderately sized grazing animal that has hooves but looks like a squirrel

and roamed the prairies around 65 to 33 million years ago. Rhodocetus was a carnivorous mammal from about 40 million years ago

Fossil evidence suggests that this animal was able to move between land and water

It had a fused pelvis and mobile leg bone. Scientists know that modern whales are closely related to artiodactyls, even totungulates like deer

You may have also heard of terror birds, and I'm sure from the name you can imagine the implications

These apex predators roamed the planet from 62 to 2 million years ago

and many of them stood between 3 and 9 feet tall. They were flightless, but this loss of mobility only seemed to motivate them to become as

intimidating as possible. At least superficially. It's actually thought that depending on the species, they subsisted mostly off of small

rodents and lizards. Another well-known but classic relative of our collective past is Australopithecus afarensis

like our friend Lucy here, looking stunning at a ripe old age of 3.2 million years old

A afarensis survived on our planet for more than 900,000 years, which at this point is

more than four times as long as our own species has been around

But at least we have pizza delivery. If you've ever been curious about the difference between a mammoth and a mastodon, then the

easiest way to tell is by taking a look at their teeth

Mammoths have teeth like our modern day elephants, but the teeth of a mastodon have high peaks

and ridges. Which makes sense because mastodon is Greek for breast or nipple tooth

We were still hunting and eating these guys up until about 10,000 years ago

Another notable and difficult to ignore ice age mammal is Megatherion, the giant ground sloth

I bring these guys up because they are one of the largest land mammals to ever live

and we are still feeling the negative effects of their extinction today

Big animals mean big poop, so the sudden decrease in distributed fecal matter

means there's a lack of nutrients in the soil, like phosphorus, which help to promote healthy forest growth

The Irish elk is another one of these giant ice age megafauna to disappear from about 11 years ago although it not entirely certain if it was due to climate change or over hunting by that pesky species Homo sapiens

Irish elk is a bit of a misnomer since they were still found in parts of North America

and they compare more favorably to deer than elk, but true to their megafauna nature, they

had racks that measured up to 12 feet across. The passenger pigeon is worth noting because of the sheer improbability of its extinction

It was the most abundant bird species to ever exist, and gigantic flocks would sometimes take 14 hours to pass overhead, their feces raining down like snow

Because of the European invasion of North America and our insatiable urge to fire off bullets into large herds of animals, the passenger pigeon was considered extinct in 1914

The pig-footed bandicoot is the cutest marsupial to ever have walked on one hoof

It had cloven hooves in the front and a single elongated toe in the back

A 19th century naturalist described its locomotion like a broken down hack and a canter, apparently dragging its hindquarters behind it

The poor bandicoot was considered extinct in the 1950s after over farming in Australia

Even though they're gone, scientists are trying to bring back the recently extinct gastric brooding frogs

There are only two known species ever to exist. They were discovered in the 1970s and gone by the 1980s

But they are the only known animal to ever give birth through their mouths

And it's hard to say because it's hard to believe. The female would swallow her recently laid eggs and then keep them in her stomach until they were fully developed

And then when they were ready to come out, she would forcibly vomit them all out at once, sometimes up to 26 at a time

This week's question comes from Lily K, who asks, Is it true you have to wait a half hour after eating before you go swimming

It is an old wives' tale that you will get a cramp and drown if you go swimming immediately

after eating, but maybe you should just give yourself a little break anyway

If you've got a mind-blowing question that you would like to see answered, make sure to leave it in the comments below

I'm Emily Grassley of The Brain Scoop, and don't forget to be awesome